Safety crash barriers are used to prevent vehicles from leaving the roadway and so to improve road safety and especially passengers' safety.
Road safety barriers are widely implemented nowadays by solid concrete crash barriers used as an alternative to the traditional steel crash barriers. These barriers are some times fabricated from combinations of different materials, such as plastic, steel, wood, or metallic cables, for example.
Many of the solid crash barriers used nowadays are a type of the so-called “step” barrier”, or the “New Jersey” barrier (or Jersey wall), which is a cast-in-place or a modular precast concrete barrier having a stepped profile designed to reduce the injury to passengers of a vehicle in cases of incidental contact, and to prevent car crossover. In many cases the stepped design of these barriers deflects the colliding vehicle back to the traffic lane and prevents passenger injury and damage to the colliding vehicle.
Concrete crash barriers are designed to direct the colliding vehicle along the face of the barrier in the direction of the traffic flow, to limit the vehicle contact with the crash barrier to the base of the barrier (i.e., the stepped section or slope) and the vehicle wheels, such that the vehicle's wheels and its suspension system absorb the impact, which in most cases allows the vehicle to return to its lane almost undamaged with minimal injury to the passengers. These features are of immense importance and desirous in newly developed road crash barriers, such as provided in the present invention.
Some times, however, the colliding vehicle “stops” on the crash barrier, or goes over the crash barrier. In both cases the pressure and impact on the passengers in the vehicle is very intense and dangerous.
Concrete crash barriers have many advantages over the traditional steel crash barrier, to name a few:                compliant to all vehicles, including most buses, coaches, trucks and light vans up to 13.5 tons (whereas steel barriers are only useful for cars up to 2 tons in weight when taking in account cost economy);        substantial reduction of chances of vehicle crossing central reserve and reaching the opposite lane or falling to a lower surface (e.g., chasm);        substantial reduction of maintenance costs (concrete step barrier requires almost no maintenance or barrier repair, and usually there is no need for lane closure-after incidents which also reduce chances of incidents during repair process); and        having a life duration of about 50 years (compared to 25 years of traditional metal barriers).        
Safety crash barriers are categorized by a severity index known as ASI (Acceleration Severity Index). The ASI index indicates the possible injury level to vehicle occupants in case of an impact with the barrier. The higher the ASI index, the greater the risk of passengers injuries. Most concrete stepped barriers have an ASI of about 1.6 (the pre-cast high cost concrete barriers have ASI of about 1.0-1.6 and therefore their use is very limited) which may not be acceptable in most cases (by law or code), and also have higher risks for severe injuries.
An improved stepped concrete design is described in U.S. Pat. No. 7,722,282, the entire disclosure of which is incorporated herein by reference, in which the crash barrier is comprised from a plurality of modular elements having a shoulder section and coupling means designed to resiliently interconnect the elements.
There is still a need for solid safety crash barriers, possibly made of concrete, metal, wood or plastic, having improved abilities to absorb vehicles impacts, prevent the colliding vehicles from going over to the opposite lane or fall to a lower surface, and deflect colliding vehicles back into their lanes, while minimizing passengers' injuries.
It is therefore an object of the present invention to provide a safety crash barrier made of solid elements, such as concrete elements, combined sometimes with other materials or elements, having improved impact absorbance capabilities.
It is another object of the present invention to provide a method for constructing and upgrading (repairing) solid safety crash bathers having improved impact absorbance capabilities.
It is yet another object of the present invention to provide a method of converting conventional concrete barriers to comply with principles of the crash barrier of the present invention to improve their energy absorbance properties and improve their ASI values.
It is a further object of the present invention to provide a crash barrier mechanism effective for preventing or reducing passengers' injuries and vehicle damages, and which is relatively simple, easy and cost effective, to repair and construct.
It is yet a further object of the present invention to provide a crash barrier that is strong, massive and of low costs for maintenance and low cost to manufacture and assemble comparing to precast methods, and having improved elasticity and/or flexibility, and energy absorbing, properties.
Other objects and advantages of the invention will become apparent as the description proceeds.